The present invention refers to a digital reading device for facsimile apparatus comprising a light source for illuminating the document to be read, means for directing the image of a line of the document thus illuminated on to a series of reading elements for generating a series of response signals in response to the points read along the line, an A/D converter operative on the response signals to provide digital signals, and means for coding the intensity of the digital signals according to a half tone scale.
In known apparatus of the aforesaid type, a given pixel of an image generates a signal whose intensity depends on the position along the image line of the original image point in the document, because of the different effect along the line of the means for directing the image on to the reading elements, the state of the illumination lamps, the variation in the time of response of the individual reading elements and the different response by one reading element to the other.